No lawsuit has been filed against the city, but the feds say a claim alleging unfair treatment over red hair would be supported by federal law, which bars workplace bias against applicants and employees based on race, national origin, skin color, religion, sex or disability.

Red hair qualifies because people with that color are found in higher numbers in Britain and Ireland than elsewhere, according to the federal Equal Employment Opportunity Commission.

Experts say it’s 13 percent in Scotland and less than 1 percent in most countries in Asia, Africa and South America.

“It’s an innocuous-seeming criteria, but if it has a ‘disparate impact’ on a certain racial group, red hair could be considered the basis of discrimination,” said Justine Lisser of the EEOC in Washington, DC.

The NYPD has one of the most racially and culturally diverse workforces in the country, but includes a large percentage of officers of Irish descent.

Some claim they’ve endured years of ridicule over their hair color.

One retired cop told The Post that he was constantly roughed up as a kid and called a “red-headed devil.”

“You get abuse every day when your hair is red,” he said. “You get beaten and chased. You better learn how to fight.”

The issue is a hot topic in Britain, where model Lily Cole, who sports cinnamon curls, blasted teachers for allowing bullying to go on “because there isn’t a stigma around it.”

Still, some shrugged off any need to protect the NYPD’s ginger set.

A retired Irish-American cop who was one of two redheads at his Brooklyn precinct enjoyed the good-natured jabs he exchanged with fellow officers, who were mostly of Italian descent.

“I never felt I was a minority,” he said.

“To put redheads in a protective class — that’s ridiculous!” said a retired officer who was often called “Carrot Top.”